1. Field of the Invention
This invention relates to an apparatus for automatically mounting an electronic circuit element on a printed circuit board, and more particularly to such an apparatus adapted to deal with an electronic circuit element having two lead wires of the large interval, that having two lead wires of the small interval and that having three lead wires.
2. Description of the Prior Art
An apparatus for automatically mounting an electronic circuit element on a printed circuit board is generally adapted to separate, from a chip tape 3 having electronic circuit elements 1 arranged in a row on a holding tape member 2 as shown in FIG. 1, a section 4 of the tape member 2 having one electronic circuit element 1 held thereon as shown in FIG. 2(A), and remove the electronic circuit element 1 from the section 4. The electronic circuit element 1 removed from the section 4 is then fed to a mechanism for guiding an electronic circuit element to a printed circuit board by means of a transfer mechanism.
Such a transfer mechanism is generally constructed in a manner as shown in FIG. 3. More particularly, the conventional transfer mechanism shown in FIG. 3 comprises an outer block member 10 fixed on a rotary table or the like, an intermediate block member 11 slidably fitted in the outer block member 10, an inner block member 12 slidably fitted in the intermediate block member 11, and a fixed pawl 13 formed at the distal end of the inner block member 12. The transfer mechanism also includes a pair of movable pawls 15 pivotally mounted on both sides of the inner block member 12 by means of pins 14, which are urged to normally open by a spring means.
In the conventional transfer mechanism constructed in the manner described above, the holding of an electronic circuit element 1 is carried out by downward moving the intermediate block member 11 and inner block member 12 together to allow the fixed pawl 13 of the inner block member 12 to be inserted between lead wires 1A of the element 1 and downward moving only the intermediate block member 11 as indicated by an arrow E to close the movable pawls 15, to thereby securely hold the lead wires 1A between recesses 16 formed on the both sides of the fixed pawl 13 and the movable pawls 15.
The recent miniaturization of an electronic circuit element causes an electronic circuit element having an interval of 2.5 mm between lead wires as shown in FIG. 2(B) to appear as well as that having the interval D of 5 mm as shown in FIG. 2(A). Also, when an electronic circuit element is formed to have three lead wires as shown in FIG. 2(C), this causes the interval between the adjacent two lead wires to be 2.5 mm.
Unfortunately, the conventional transfer mechanism, as noted from the above, is constructed to deal with only an electronic circuit element having an interval of 5 mm between the lead wires.
Such a disadvantage is also true of a conventional mechanism for guiding an electronic circuit element to a printed circuit board.
Accordingly, it would be highly desirable to develop an apparatus for automatically mounting an electronic circuit element on a printed circuit board including a transfer mechanism and a mechanism for guiding an electronic circuit element to a printed circuit board which are capable of effectively and positively dealing with an electronic circuit element having two lead wires between which the interval is 2.5 mm and that having three lead wires as well as that having two lead wires between which the interval is 5 mm.